A ground ring electrode must completely encircle a building or structure and be buried at what minimum depth?

The correct answer is 30 inches. A ground ring electrode is designed to provide an effective grounding system for a building or structure by encircling it, which helps in stabilizing the voltage during transient events and improves safety by directing fault currents into the ground. The minimum burial depth of 30 inches is specified to ensure that the ground ring electrode is properly installed beneath the frost line in many regions, which helps to prevent damage from frost heave and ensures consistent grounding performance.

This depth also reduces the likelihood of physical disturbance and maintains the integrity and continuity of the grounding system over time. Grounding is critical for the safety of electrical systems and protecting both equipment and individuals from shock hazards. A properly installed ground ring at this depth effectively connects with the earth to carry away fault currents safely.